Machine for flattening filamentary wire



July 7, 1931. s. WADSTEN' MACHINE FOR FLATTENING FILAMENTARY WIRE 2Sheets-Sheet 1 Filed July 8, 1929 INVENTOR ATTOR E v Patented July 7, 1931 I UNITED STATES PATENT oar-ice STEN WADSTEN, OF BLOOMFIELD, NEWJERSEY, ASSIGKOB 1'0 WESTINGHOUSE LL11? COMPANY, A CORPORATION OFPENNSYLVANIA FOR FLATTENING IILAIEHTABY Application filed July 8, 1929.Serial 110. 376,587.

This invention relates to the manufacture of electron emission devicesand relates more a particularly to production of a flattened filamentarywire for use as a cathode in such devices. I I

In the manufacture of certain types of electrical devices such as radiotubes, it is desirable to use a cathode consisting of a suitablemetallic core such as nickel or platinum iridium alloy or of a suitablenickel alloy. The

core material employed for cathodes of the above character is initiallyproduced in the form of a wire circular in transverse cross section. Itthen becomes necessary in order 15 to obtain the required voltage andamperage characteristics and the desired surface area to maintain aproper operating temperature to compress or roll out the core into aribbon of a given thickness.

By reason of the minute dimensions of the wire, great difficulty hasbeen encountered in attempts to successfully produce such wire inflattened form having a uniform thickness throughout its length. Forexample, a filamentary wire or core for a-radio tube such as that knownas the 171A has an initial diameter of .0022 and must be flattened to awidth of .0046 having a thickness of .0006. When compressing a finehair-like body, such 30 as a filament wire, it hasbeen found not only tobe necessary to employ a mechanism constructed with .precision but toprovide a novel combination of machine elements so arranged andco-related as to apply the required pressure in a delicate and accuratemanner to compress an initially round wire into a flat stripof'predetermined dimensions,

It will be appreciated that in the ordinary operation of rolling, as forexample, the rolling of bodies, such as sheet metal or the like,

slight inaccuracies in thickness occur throughout the ama of the bodyafter rolling by reason of the variation in the properties of softnessand hardness of the material.

Under ordinary conditions such inaccuracies as do occur are notappreciable and have no detrimental effects in the ultimate product. henflattening a-filament wire, however, of say .0022 to .025 of an inchdiameter wherein the final thickness of the wire is in '-l he dimensionsof thousandths of an inch, it will be readily appreciated that anyvariations in such thickness will be relatively great and effect theoperation of the flattened wire when used as a cathode. This isparticularly true since the wire, is used as a resistance eienient forflow of electrical energy and is susceptible to variations in itselectrical conductivity if the dimensions of its cross sectional areavaried throughout its length.

It is an object of the present invention therefore to provide anapparatus for avoiding the above mentioned difliculties and to produce ametallic ribbon core for use as an oxide coated cathode which will havea uni+ form cross sectional area to give the required resistance foroperation with the desired voltage amperage characteristics at a givenop erating temperature.

Another object of the invention is to provide a filamentary flattenedcore material having a uniform cross section at all points throughoutits length.

Other objects and advantages of the invention will be more fullyunderstood by reference to the following specification together with theaccompanying drawings in which,

Fig. 1 is a side elevational view of a. machine embodying the presentinvention.

' Fig. 2 is an enlarged plan view of a portion of the machine shown inFig. 1 partly in section to show internal structure.

Fig. 3 is a vertical section of the machine taken on line 111-111 inFig. 2 and showing a power or driving unit. 7

Fig. 4 is a fragmentary view of a portion of machine showing anadjustable guide, an

Fig. 5 is a perspective view of a portion of a mount for an electricaldevice showing a flattened filamentary wire as used in practice.

A machine constructed in accordance with the present invention comprisesa pair of pressure rollers having operative surfaces of substantiallyequal length and rotatable on parallel axes. The pressure rollers arearranged one above the other and are each en- .closed in a journal box.These rollers are provided with dressed or finished surfaces normallydisposed in close relation to each other and each of the journal boxesis provided with a bearing surface area greater than one half the areaof the operative dressed or lapped surface of a roller.

The lower journal box is supported in the bottom of a guide bracket andthe'upper journal box is disposed within the upper portion of the guidebracket or hanger and tensionally held in position so that it may bemoved toward the lower roller for contact therewith in the absence ofany force due to the potential energy of the said suspended upper rollerand its journal box, thus making it possible to adjust the rollers to anextremely accurate space relation for contact with a wire disposedtherebetween without subjecting the wire to the weight of the upperrollers, means being employed for obtaining a micrometer adjustment forthe rollers.

' For the purpose of avoiding the transmis-- sion of any inaccuraciesfrom external mechanical driving elements which rotate the rollers theyare coupled with a power unit by means of a loose coupling or lostmotion connection. When the pressure rollers are rotated therefore, thedesired extreme accuracy with respect to their space relation ismaintained and the filament wire fed thereto may be compressed to anaccurate cross sectional area, the dimensions of which will be helduniform throughout the length of the flat- I tened strip produced.

A practical embodiment of the machine may, as illustrated comprise aguide bracket 10 secured by bolts 11 to a bed plate or table 12. Thebracket 10 may comprise vertical side plates 13 and 14 disposed inspaced relation to provide a guide slot 15. A heador cross piece 16 issecured by tap bolts 17 to the upper ends of the side plates 13 and 14and within the guide slot 15 are disposed journal boxes 18 and 19. j r

The rollers 21 and 22 are positioned in the journal boxes 18 and 19respectively and the journal boxes are at least equal in length tooperative portions of the dressed surfaces 23 and 24 of the rollers. Thelength of the operative portions of dressed surface are indicated byarrows A in Fig. 3 and the journal boxes are provided with bearingsurfaces 25 and 26 so formed asto provide a rounded slot be insertedinto the journal boxes by being thrust into the slots endwise, a segmentof each of the rollers projecting from the journal boxes for engagementwith a wire 27 fed from aspool 28.

The journal boxes are arranged with the journal box 18' above thejournal box 19. Thus the roller 21 constitutes the upper roller and isdisposed with its axis of rotation above and parallel to the axis ofrotation of the lower roller 22. A pair of tension members in the formof flat springs 29 and 31 are disposed between the journal boxes andserve to normally urge the journal box 18 upwardly and thus prevent theweight of the journal box and the roller 21 from being applied to thewire to be compressed between the rollers 21 and 22. For the purpose ofadjusting rollers to a predetermined spaced relation, the head 16 isprovided with micrometer threaded screws 32 which pass through threadedapertures 33 in the head 16. Graduated scales 34 and indicators orpointers 35'are provided so that as the screws 32 are rotated byengagement with nuts or heads 36 the journal box and roller may be givena predetermined degree of movement.

A shim 37 0f hardened material may be disposed between the journal box18 and the lower end of the screws 32 so as to provide a replaceablesurface when worn. It has been found desirable to provide the rollerswith a' film of oil or lubricant and for this purpose an oil cup 38 isprovided having a conduit 39 leading to a passage 41 which communicateswith the dressed surface of the upper roller 21, so-that a film of oilmay be carried around the rollers.

It is desirable to have a sight-feed for the oil so that trials may bemade to obtain the proper amount or film thickness after which the valvemay be set to give a continuous feed of the proper amount.

It is important when flattening a fine wire of the character operatedupon by the pres-' These force screws pass through threaded apertures inthe plate 14 and engage with the outer surface of the journal boxes.After the rollers 21 and 22 have been properly adjusted to the requiredspaced relation for the flattening of a wire, the force screws 42 and 43are manipulated and the journal boxes are compressed between the ends ofthe said screws and the side plate 13 sufficient force being applied toslightly spring the ournal boxes and more tightly compress their bearingsurface in contact with the dressed surfaces of the rollers '21 and 22,thus providing the desired intimate contact between the dressed surfacesof the rollers and the bearing surfaces of the journal boxes.

The wire 27 ma be led through a guide 44 carried on an a justablesupport 45. The guide 44 may be of tubular form and preferably of somesmooth material such as a vitreous coated metallic tube or of aglasstubular member, an end. 46 of which extends be-. tween the journal boxand in close proximity to the oppositely disposed surfaces of thepressure rollers 21 and 22. The wire 27., after passing between therollers may be collected on a spool 47 the said spool being mounted on aindle 48 carried in a bearing bracket 49.

above mentioned the entire length of each' of the pressure rollers isdressed or lapped and is effective for the flattening of a mm as shownin Fig. 4. The dressed surfaces of the rollers may be termed theoperative pressure surfaces and the bearing surfaces of the journalboxes may be termed the efiective bearing surfaces. The wire to becompressed may be fed to any point between the operative pressuresurfaces.

For the purpose of guiding the wire to a selected point the support ofthe guide 44 is secured toparallel strips 51 and 52 disposed at oppositesides of and beneaththe heads of tap bolts 53 and 54 which secure thestrips in position and hold the guide in given relation to the rollers21 and 22 by manipulating the screws 53 and 54. The support 45 may beadjusted with respect to the said rollers so that the wire may be guidedinto contact with different portions of the surfaces thereof as desired.

From the foregoing it will be evident that the rollers 21 and 22 areself contained insofar as the o eration of flattening a wire isconcerned. l lach of the rollers is provided with a bearing surface ofsuch character P that the roller is held accurately in position and thespace relation between the rollers is constantly maintained.

When rolling a filament wire to the dimensions necessary for theproduction of a filament or cathode base, it is important that thepressure'rollers receive motion from a power unit without having theiraccurate relation disturbed by inaccuracies which might be translatedthrough connection with the power unit. In the present construction thepressure rollers are therefore provided with ends 55 terminating insquare headed shanks 56.

A link 57 and couplings 58 and 59 connect the shank of the upper roller21 with a squared end 61 of a shaft 62 having thereon a gear wheel 63,suitably journaled in bearings 64 and 65. The gear wheel 63 is disposedin mesh with the gear wheel 66 secured to a shaft 67. An end 68 of theshaft 67 is provided with a sprocket 69 connected by a chain 70 thebearing surface.

with a motor or other suitable source of power, not shown.

An opposite end 71 of the shaft 67 is squared and connected by a link 72with shank 56 of roller 22 by means of couplings 73 and 74. The'linkconnection for the transmission of rotary motion to the rollers is of aflexible character or a lost motion connection so that the rollers 21and 22 may be rotated without being subjected to any external forcewhich might disturb their said space relation. The gears 63 and 66 whichare mounted in a gear box -7 may be considered as a power unit.

For the purpose of preventing endwise movement of the pressure rollersstop plates 73, 74', 75' and 7 6' are provided. These stop plates engagewith the shoulder atthe outer edge of the extended portions 55 of therollers and serve to prevent end thrust.

For the purpose of rotating the spool 47 to gather the flattened wirethe shaft 48 is provided with a pulley and a belt 81 con nects thispulley with a pulley 82 (see Fig. 3) secured to link 72 so that motionis translated to the shaft 48 and the spool 47 rotated and the flattenedfilament wound thereon.

When flattening wire of nickelor nickel alloy fine particles of materialbecome loose and adhere to the-surface of the rollers.

It has heretofore been found that when flattening such wire this finedeposit of material tended to wear grooves in the rollers or otherwisedestroy the smooth surfaces necessary for accurately flattening thewire.

In the present invention a number of pockets 77 are provided in the formof slots in The slots extend between ends of the bearing surfaces andduring the rotation of the rollers the particles of material whichadhere to the surface of the rolliirs are scraped off and depositedin...the

oc ets.

are provided they are only necessary should an excessive amount ofmaterial accumulate since it'has been found in practice that whensupporting a pair of pressure rollers for rotation in the manner abovedescribed, the close relation between the rollers and the bearingsurfaces attainable by the present construction, serves in conjunctionwith the particles of material which free themselves from the wire tocontinually lap or dress the surfaces of the rollers and maintain themAlthough the pockets above referred to -ot' the contacting wire, aresmoothed out accuracies of the grinding wheel. The procedure of lappingby the usual machine shop practice results in a cylinder having the mostaccurate portion between its ends.

In the case of the present rollers the surfaces indicated as A are thetrue or operative surfaces and are disposed for rotation in the bearingsurfaces and 26. The ends 55 of the rollers project from the bearingboxes but do not function as bearings. Thus the total bearing surfacesfor the rollers consists-of the bearings 25 and 26 which are in contactwith the operative or effective pressure surfaces A of the rollers 21and 22.

By reason of the construction and arrangement of the journal boxes andthe rollers, the rollers are self dressing since they intimately engagewith the bearing surface of the journal boxes and inasmuch as thejournal box bearing surfaces partly surround the rollers, a large areaof contact is n'iaintained. By reason of the force screws 42 and 43 thediameter of the bearings may be changed and a more intimate contactbetween the rollers and the bearing surfaces may be attained whichoperates to provide not only an accurate bearing but a surface fordressing the rollers continuously while in operation.

Heretofore in machines wherein the usual pressure rollers were providedhaving their ends journaled in bearings the inaccuracies of the bearingswere imparted to the rollers and accuracy, insofar as the dimensions ofthe flattened wire were concerned, was unattainable to the degreenecessary in an article of the character to which the present inventionrelates.

In the present invention, however, where the operative pressure surfacealso constitutes the bearing surface of the rollers and where therollers are rotated in a manner which may be considered independent ofthe source of power the required given spaced relation between thepressure surfaces of the rollers is maintained.

Practice has demonstrated that after long continued service the pressurerollers of a machine constructed in accordance with the foregoingdescription are free from surface irregularities which would otherwisetend to make inaccurate winding and that the close contact between thebearing surfaces and the effective pressure surfaces of the rollersserves to continually dress the rollers and any slight impressions thatmight be made by reason when a roller passes over its bearing surface.\Yhereas heretofore in other machines for flattening filament wire, itwas necessary to cl'iange the rollers or shift'the' position of the wirefrequently by reason of the groove v n'n in .he rollers by the passageof wire under compression.

The present machine has operated cont-inuously for a long time periodwithout changing the position of the wire and without having itsdefective surface deformed in any way so as to effect the .production offlattened wire having the required dimensions in its cross sectionalarea through all portions of its length.

It will be readily appreciated that the present mechanism, since theupper roller is normally supported by the tension members the weight ofthe tension box and the roller, plays no part in the pressure applied tothe .wire, and that the adjusting screws may adjustthe upper roller sothat a given space relation is maintained between the upper and lowerrollers, thus the applied pressure is uniform and if the wire Varies inits degree of hardness or softness, such variation will not affect theoperation of the rollers in producing a wire of uniform thickness.

This. as hereinbefore. mentioned, is of extreme importance in connectionwith the forming of a cathode 84, as for example, that shown in Fig. 5,wherein the length and transverse cross sectional dimensions are ofimportance in determining the resistance of the cathode making itpossible to meet manufacturing demands in the production of an electronemission device such as a radio tube having given voltage and amperagecharacteristics.

Although a preferred embodiment of the invention is shown and describedherein it is to be understood that modifications may be made thereinwithout departing from the spirit and scope of the invention as setforth in the appended claims.

What is claimed is: i

1. A machine for flattening a filamentary wire comprising pressurerollers, dressed surfaces on said rollers, bearings partly surroundingsaid rollers, the total bearing surfaces of said bearings engaging saiddressed surfaces of said rollers and means for changing the diameter ofsaidbearings to vary the degree of contact with said dressed surfaces.

2. A machine for flattening a filamentary wire comprising a pressureroller, a bearing partly surrounding said roller and means for changingthe diameter of said'bcaring to vary the degree of contact between thebearing and said roller.

3. A machine for flattening a filamentary wire comprising a pair ofpressure rollers, a journal box for each roller, bearing surfaces partlysurrounding said rollers and vmeans for applying a lateral force tocompress said bearing boxes to change the degree of contact between saidbearmgs and said rollers.

4. A machine for flattening a filamentary wire comprising a. pair ofpressure rollers, a journal box for each roller, bearing surfaces Ipartly surrounding said rollers and means for compressing said bearingboxes to change the de cc of contact between said bearin s and sandrollers and means for adjusting said journal boxes to change therelatlve position 6 of said rollers.

5. A machine for flattening a filamentary wire comprising a air ofpressure rollers, a

' bearing box for eac roller, bearing surfaces partly surrounding saidrollers and means for 10 adjusting said bearing boxes to change therelative positions of said rollers, and means for var ing the de ee ofcontact between said ro ers and sai bearin surfaces.

In testimony whereof, have hereunto v 15 subscribed my name this 5th dayof July,

STEN WADSTEN.

